4t60 shift modulater

[l67ss]

Unhooked and plugged off my tranny vaccumn modulater now it idles better shifts better AND smoother and it sounds better guessin bad shift modulater?

[RobertISaar]

sounds like it. sometimes they fail by the plunger diaphragm rupturing and suck trans fluid through the vacuum line. sometimes the vacuum line itself is the entire problem.

[l67ss]

I hav had to periodically add atf bout one half to a full quart a month

sounds like it. sometimes they fail by the plunger diaphragm rupturing and suck trans fluid through the vacuum line. sometimes the vacuum line itself is the entire problem.

[l67ss]

Prolly not even gonna change it ill jus leave it capped off drives better that way than it did wen da valve was working right even the brakes feel bettet

[l67ss]

Bout like an old th350 then

sounds like it. sometimes they fail by the plunger diaphragm rupturing and suck trans fluid through the vacuum line. sometimes the vacuum line itself is the entire problem.

[RobertISaar]

they actually use the same modulator. that's how we get adjustable modulators a lot of the time, since very few places list them for a 4T60E.

[Schurkey]

If your transmission shifts "better" without the modulator being connected to vacuum, either you have an odd sense of "better" (high rpm shift points and harsh shifts) or your transmission is in deep, deep trouble.

 

As for the engine running better, could be you have a massive vacuum leak in the vacuum plumbing; or the engine simply did not appreciate sucking trans fluid into the intake manifold.

 

A proper repair of the modulator system should result in retaining the improved idle, along with proper and realistic transmission pressures and shift points/shift quality.

Edited September 1, 2013 by Schurkey

[l67ss]

It shifted like a granny car b4 the valve went bad not to worried about it as im goin sc 3.8/4t65 the filter does need changed

If your transmission shifts "better" without the modulator being connected to vacuum, either you have an odd sense of "better" (high rpm shift points and harsh shifts) or your transmission is in deep, deep trouble.

 

As for the engine running better, could be you have a massive vacuum leak in the vacuum plumbing; or the engine simply did not appreciate sucking trans fluid into the intake manifold.

 

A proper repair of the modulator system should result in retaining the improved idle, along with proper and realistic transmission pressures and shift points/shift quality.

[l67ss]

Kool

they actually use the same modulator. that's how we get adjustable modulators a lot of the time, since very few places list them for a 4T60E.